SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efca7033de243a61a956ce89a4d435a0aebd934c9ed13a0be460a2f40142b0c6' 
  AND token = 'y/RvNL9foL7cmqSiZqiEtZnnQ1SXZ6rRnVzdoVMVZwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}