SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '736e960679fbbe305d1e4b9f6b55e88e9cf2a93fda78c9cfc1755fc3baf828af' 
  AND token = '7rwBfYvEhZl7XfFfVu27qDTitmdJulh8g6mp6f42/6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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