SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48f92f373c800b1bbf9eea87b976b6641c586d4902f4a1f4204eaa3622bc595d' 
  AND token = 'KBgqdtlKSoYDnEMjKfd5a9XplvyXQuIK2oH/s7ZcNVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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