SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c872a1d86164b58de9c39d37282223d93bd2a74220efc742cf7852134d4c7ee4' 
  AND token = 'eTMGlWZRwifoN/XYy8Z6fVgZJZPGvlhnT1qlCKiIzmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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