SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cad18980c0607566b94574b7411b37c082d2c5ad8bc148b2c36cdee908d7ce7c' 
  AND token = 'Rb8DY5yfNczm757qMdsR1g4mpyOMFKfzmDomQgn/IjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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