SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2237ca6f3ab5231230c410a149e2c472fc6add20864dab99e655512a9640afbe' 
  AND token = 'dc3nhNj9KAfotShfcBNE8oj17BQ0H+WZwFPwDC7GdOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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