SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99b6503cae5ded116327fc8fee6d2e55042a2b92738412f352d2c2b3153e54a8' 
  AND token = 'GM+44/Evmyb+2Z3XUFhCKylFMM4JJfAlIWhwsOHicEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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