SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e2425cdeea42c3bb05719778309d5b639b5e5dbbc118a1e1953e0c3db34e4af' 
  AND token = 'qY/+GnXKTeT0Oj3g81rYHS7pIqyGSwEYFzFRRhDy9uY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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