SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a2e49cac827f329cc23f621a300313dd6446c4029649698a7406cff4279b0e3' 
  AND token = 'RvqSuykHLhyqJHB/6XUkVG9LN4wpewdf30aamEM7ugo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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