SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fd138321122f5992f9e8466ad4712dac6ed94ca46d9cede7de6dca1ca95c25a' 
  AND token = 'ot8iMjJchgyAEK7syfP0u90g73dN8cKZ/pWxqm0muWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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