SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '337b3c026a055f96a47955fdc9ca60a80c6f489490b76f3e6adecdd6a0937cbe' 
  AND token = 'VOLY5rIEgnmnYUjGqyWLEw4c/sQFCSp0ZvFCd+79DcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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