SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f031e390f0038f3f243feeb121bad0955c4a013dc25fa1ea7968444a75ea2fff' 
  AND token = 'QnsEiksdguNBkDIDN2/4tbXjFaBirgWmU/Jaxc7aZVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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