SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b6065730b4e5106046a2005c67d5574fdabb9a7e1d021624793f6a158a2c2d3' 
  AND token = 'FeilVMs2n05AT7ZBBhvz2+vXCtqIFSpmHx7VUvZjwDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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