SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96e7aa564f2eafcbfc83e5196d94411a736e9e44652b5a3168b3c96cce22fbd9' 
  AND token = 'oRh4ofpUE3RN3EAUdiWOvbjAnlNfBpdNbpKVqSW0hZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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