SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64dc839f8b9fe6d58c48310e263fe27fd2f525c233f6d249bb02db8a5d18610a' 
  AND token = 'NQj0SqYyFCRVYAfa/X7tjD/cvDNq+/MlKpzj6E7Q6OM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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