SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02d5261434786a0340d370c2c0caf8cc683dfe5ef46965938283bae68503a503' 
  AND token = 'kwKTZzYHHMpc1gcvyDYaol24n3Or1lBq3Ws1qKg90QQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}