SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '906efb8a8e8b8a1af19b2738d432a1c212cda7dbe70dd3d031dbe13735133594' 
  AND token = 'yCaDwOCuXfkvTudXDFU0bByF3Nv4wUhiAaSCZV+ZKS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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