SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8be9c351816510858be04994fcc4fce2fd4925979110e7815f4af1243bc33ff6' 
  AND token = 'PtWmjQYdvwNx/IAZPkGxTaqjryVopTvTsyjR2Za3Yqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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