SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12e50ced4ab96b5da884109b1af23d31ecbd9b2e23a802b60078e24d3f0f4a53' 
  AND token = '2pz8n5e+qXMK5TCyK4FZFJB0KF9ORBFyvtIomcG5Tz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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