SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac84b1ede3fd7b56b5034d1d2aba438de5be3e27f9e82eee031bb70b420014d4' 
  AND token = 'L+578XUdDa2U55mzOmuMddMyoEEM7j7/ony8hD6n9GQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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