SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e90fc5939b1c3a8893b0a39a5635be84d31a25ad603461374696d854b031534' 
  AND token = '8lsR6VBIodzT+hzPlKENDqV0yvXnFjMl2aJzQ0jVDNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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