SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0f538b9815b511b0206d19925451764ecd11d27bd46e060b2a37aadd75855c4' 
  AND token = 'nZG6PBqAOQRMogVPk4fjLZOuDXYVIlqx4Xw2/e9P0W8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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