SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3396efaab2bc012ff261c12b98b930abd51da2c7322b0c68e9323c404599aa70' 
  AND token = 'X9gIuvdlPoaI7rK9egebfipQYvZJkOHNnmGqyR6q6ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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