SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53457be2cdfb1c82c8f29f9899246319f77d3b5141aff99ff1196e701d23dcf2' 
  AND token = 'kPCV2/WrgWrv26gke/rUWNnCHb0LMxpwsMboK7mglTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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