SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac953ecc0d3d0771e540b1a20aae4f9b0dade67f8a517573f35e832cfd963ad9' 
  AND token = 'ME6vufPzB7FsrwXyB/QiqAxP0n2EejojB7kwXtgcexo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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