SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c82628c9e36118f999bbf919715e5500a9731ef6b4c62e23c57d91f70c678f66' 
  AND token = 'YlW2DyNr/Fr6Tsk8wksQHrwlplzXJW9yAUqy+EHAMCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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