SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52dcd296020118626d49d71abd3e5fb089268be69454b3cb3eb3f01a5d32b60c' 
  AND token = 'vwDvBB9EdxBNZw2y5tvkkHENEUa/qaYsMwyCmqRsp7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00068

JSON explain

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