SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd59f079bb18f57d2a62535c68a0d3336fafbaa595e3fa0d879d1d29d210d3e97' 
  AND token = 'j4mz+yx2PlVlWhQap/3k3PmYwXZYhsylbUklASMfgjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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