SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6b164a0aaf64cf9052fd1caec388eb5db54f792d851df2788610e7d01a78fd6' 
  AND token = 'C6VTFrAI0yjvmenBasb0HQSHn50XqzXkBldrqZlrm3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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