SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c45b194024d455cb901c434573999ea732eb8ba2728c846043e0970367962bd' 
  AND token = 'vTwPPiv6HF16gGsJWb0mfXUw/lsZXYpwqm+xlv9AkxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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