SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e912d5df424e62eb6dd91da695a7d620a096e1a4f69a0ad75207f91226aa3b93' 
  AND token = 'LA1OzrdpCxBET7tmK6tWlIC877s/HCovsLQG9002rYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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