SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11f97b0fec9fc8787c613336dd11afd3b555739c560a7cfb8853539bb3aee4c2' 
  AND token = 'VLriMJlgMJBzyMvrwYkhHDgKiha8H426quScCluvM8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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