SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2908ccb3003e76a8e8d724a978d8fee0ccf87676d5d8f1ad7dcbd76eae0d53be' 
  AND token = 'SNj/RDRPuyqze7irlKd9UREx1Xi8VEcgPCB6Pxcijto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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