SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c537c568d694c81f093bd53f8ec12cab801445b48a0c1feaf1529eb8359edc66' 
  AND token = '4qxZa04FjPkHYWnWg7+SeroKSgeXLDlwi4aDHBouDrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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