SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0420bf0d6598057680ca1da83ec9c7ddd9e12c21a772078081971797f2237a4' 
  AND token = 'JH2XBXRLiVuUR2retePiSC4I1N9U5BEt/BmPDzHjm/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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