SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71fb420c47466fb0eda22ca0ae05e8683eaa713b854f025a71a6c0fd6e115ca6' 
  AND token = '45VDboOmQP4f9v0hAfvDCu2BCIWVI+pga9VFImX1uuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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