SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c006aaa259af37324eab06fa9be095aaba2e644ade80750148c44adef6fe01e3' 
  AND token = '5jiSJp5dMph/fZAqtqiIGjBgYFNKfWbXLNeEAbOLHNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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