SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87ac718e1499c8e66a99bad1c230b1474eba10a73e68d86f219ecaaa1d08f7ad' 
  AND token = '04Khw0ohHccS+jLUGst6qsFxRPXDONfSauahFSLnwVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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