SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1528b5ba520781065940ec67cdbe200f7812a3d973216b49cdb0b50c864d9c0e' 
  AND token = '5DvWjCac+JTJ9iPO4iBciGS4oLwyy+kpZGw9AwrGQcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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