SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85e0b6af0c5db1c378789c4b414975b1f073cbdd3fd35e85ab679820a84e15a1' 
  AND token = 'wl8tlZaCMII1hKrwopqZmLi5KCJByec73OQrY+UrSHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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