SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1dabe534e2915004691d425ce05c2532a1f474995d0db41fee4d4885865c6769' 
  AND token = 'ZxF0TZRcUSDRk7KCn7tSDt5qj833aKQM1qDgOzgXBc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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