SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38cd480dea41841a6fe88a32045e17618b99a30fb79693cdd1c435697311c9dc' 
  AND token = 'qVIngsrfd+9ANebIKbIHEGqGOHnCv9aEE2PT91oaG04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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