SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b03dfeae8e0d0bee25cdd2004c6c4b8509c3406ebf21f45013f2d79b78a0638' 
  AND token = 'dteck9GKIZDsKom485Qv7T6cRbhpFJSmncTFlpekijM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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