SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b929afc57d6aebed5ac49cd06a508ef26731a6f3f58cb1db9a6362578471b1a8' 
  AND token = '0O/oxv97W48fidxv2Kg4DiBv09weMwfSfmVXsQrbk34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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