SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b35d38cb78bb1027844d84b3cbd830d623b3c220d715221424304b83270b78d0' 
  AND token = 'OfqaoAsOLzn5RvLLk9m8Dk2EjpDRXptBcVzioYRhqQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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