SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b66ebe649782a905ead62f84e136340f293e65ebe19b178f70e7658316f407c' 
  AND token = 'Dvaix8XxVu5mGStsdYUt6fou+1yv5KoaJmz5gkAAJyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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