SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7c4273852646ce1d189eb16c19ae4bd8079bcebee5852a98125e385c3e08158' 
  AND token = 'FHDQ13KBR2zOQQs+hx1Ae1EtXbZYGtG6OEbFRCmAt5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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