SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '919b7465809b4699f4c5b7ef4ffa199ae9d399c438f186c4598093c2ebdffbec' 
  AND token = 'H8rNOslrvTsFDJ7jCGHxQsRIVT2MdInzmpOPVl01CqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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