SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41b7d68fe761d4ff053a484842c6ad79ff772783dc923990e928c92067b55678' 
  AND token = 'PKwEUbHboHT9yNK+Iq0Rj7SzwC2e3jyT7uwQvus/5yI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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