SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b54042708215277ea86fcff4a650fa9ce84440fb49b044a420d4cf3bec6c5375' 
  AND token = 'AQ8m/ptbc2bzOCo3cT6cjJ+oCE+esCWXLp/aeLuQW0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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