SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a334d5476cfb47e860d793d5491c0c5ee65f3b57a28e6407c8adb4d311a6952' 
  AND token = 'OmPLTRz7K1FXrOmbQqy3SsBX+wilpfbZKSCuJwOdFe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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