SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd38399b7b37463f2c8d55007abcad19a24e14a6dfe08356277a2aa6e11d9b6a' 
  AND token = 'C3VIIeJYZxAWKmpqHpnlELi8WOm/zuA7bGg8Orb2Cz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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