SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3acaa5ca3064c3ca8d845681c199956f8ca17b64e7a41fecc9f7ac17c773803' 
  AND token = '9Yo03UT6E92B61sonurc40JQzoCQRNcRoq1ASocn81w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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