SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2512c40dbe939c31a1db416183ffb536090f917dc7c106215de565406b0d29d' 
  AND token = 'h2U5CDXgHKMBWwb7Jy2WpCQTsyeIiJYUhObrSz+0/q4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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