SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '610bcba6e7d85d18ec6222d793ad237d800239f06417c3ab020781ac8f203d17' 
  AND token = 'fFMbd2RKla+d2kiHpqqtUggWRztmYo+ewpDEas6tKto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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