SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '637e5acd7529261e720bbda5a55831055af461ff144c8bc69616a50c3ab1f939' 
  AND token = '7R2QihTlYEfDfwCJWuItM7l5YHZM2xJYvrDKAwGS2tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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