SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86ad4661b2b91c985ee059b3123c5a262a845eba18a67865b0296a6afa1e71bb' 
  AND token = 'nQSfUhmU0bM+RBB1KAFWNa/FrCPJCh6mEMOTM/ndybo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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