SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c96bdd5dfa8644f2516e79f29a83431482fae53e40ec4b9828cb773c6d7aed2a' 
  AND token = 'LmZSORHRsr0pg/zGcsmu1APNbRZdv+LhgcjXe85PCfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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