SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbc4113839dc32fe55210abecde707241ed10c58bcbf5b85a905e03e50cd2e60' 
  AND token = 'QRk2ksDpt1nQCgnC02aUA3AOt3KkQXNpqhIou92R9JQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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