SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e5df0d5c28964261d27886cf96050a93df8ae90bb09513ce7b622733746d00e' 
  AND token = 'A5U7ePN88SC33Y2gOpPdqPiyrfdaqlaN8UUPYAkYgjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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