SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69e6274af6747187a1cd330f3e4de9663354b8c0c480345290fff918db821877' 
  AND token = 'SSbMk0KI17RF4+TttTAqqYMfzdFafzkI7hyeApvdgG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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