SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a8f63f85af26cc24b2a197dde6f2d99a1a0f43e49529b377722268c9c976894' 
  AND token = 'I0E3feEWOPmYIcgz958hQv/gtiqz+alnB511WMBV1KI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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